NDS Spokes coming loose

brettjmcc

Just after some advice please what to do.

I built my first set of wheels up earlier this year on a a set of CXP22 on 36H 3x (ACI DB spokes) on 105 hubs. Whilst I was away with the bike on holiday, some of the spokes came loose on the NDS and I just did a quick tighten. Upon my return, I loosened off the whole wheel and started up again, tensioning up the DS to about 100Kgf (or 21 on the Park TM1). Then retrued and dished every thing over a few evening allowing for some destressing.

I've just ridden them again for the first time and after 35 miles, some of the spokes have come loose again.

Have I just got too little tension on the DS and then subsequently on the NDS? I have gone for 100Kgf, as I remember someone saying Mavic rims are not built for high tension, or this just the Open Pro?

If I have got the correct tension, would I benefit from using something like Spoke Freeze or Screw Lock? Or is there anything else I can do?

Thanks in advance

ugo.santalucia

You might want to go a touch higher... worst that can happen is that the rims will crack in time... but those are 15-20 quid jobs, so no big deal. If you want to use spoke freeze, don't buy the pricey stuff, just get some Loctite 221 or 222 from Ebay

cycleclinic

You need 1200N DS to get a stable wheel 1100N DS is O.K 1000N is too low. That will give you just over 600N NDS. I do build wheels with hubs that give a worse tension balance than the 105 hub leaving 550N NDS these do not get loose spokes but the tension are very even and thats the trick. You need to make sure the NDS rear tensions are very even. Spoke freeze should not be needed if you get even tension. A Mavic CXP22 rim can handle 1200N without cracking.

A wheel does not destress it self with time you know. You must grasp pairs of spoke and squeeze until your hands hurt do it enough and you get used to it and calluses develop. This grasping of spokes removes any wind up and stretches the spokes also it beds the J-bend into the hub flange. You will find a small tension drop after doing this and tensions will have to be raised again. Also placing the built wheel on its side on a block of wood and putting light load on the rim will remove some windup (pinging maybe heard), the wheel may also go out of true. So re true and repeat until the wheel becomes stable. If you have to use spoke freeze or locite you are doing something wrong.

hypster

You can't be sure that with a TM-1 reading of 21 you are even getting 1000N on the DS. The Park TM-1 notoriously reads on the high side leading to lower tensions than required. I'd push to 22/23 DS on the TM-1 if I were you and see how you get on.

It's about time you built that calibration device for your TM-1 Brett!

cycleclinic

I forgot about that. Take 10% off your spoke tension that you get with the TM-1 and you are in the ball park. how do I know I have a spoke tension calibration jig and a TM-1 I no longer use.

brettjmcc

Yes, sorry. What I meant on the destressing etc was I did the whole process over a few evenings (kids got int he way). I have a block of wood to do it.

Yes, the gauge is now on the way to build up the calibration device, life/work has been too busy!

dennisn

thecycleclinic wrote:

A wheel does not destress it self with time you know. .... Also placing the built wheel on its side on a block of wood and putting light load on the rim will remove some windup (pinging maybe heard), the wheel may also go out of true. So re true and repeat until the wheel becomes stable. If you have to use spoke freeze or locite you are doing something wrong.

+1